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1279 Views 8 Replies 4 Participants Last post by  kwplot34
I was installing an MSD 6A box, and was following the directions for wiring an MSD pro billet Dist,since that is what i will be using. Ok got it all wired and ran the original tach wire to the tach input on the 6A box. Read further on in the instructions and it mentioned a run on problem that might happen.
Has anybody experienced this probelm using the factory tach, and if so how do i fix it? and do i need to leave the capacitor in line that ran to the original dist?
Just thinking ahead in case i have a problem. Thanks in advance for your help.

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Kevin-- RTFM!!:rolling:

The run-on with an MSD box is from the alternator backfeeding the MSD box and keeping it powered. They give you a diode to stop that from happening. I didn't have any problem with my Summit/Mallory box. And they also said it doesn't happen on all cars. If you'd just do the simple thing and swap to a mechanical tach you wouldn't have to worry..:D

That would be to easy Tim :laughing: on the dizzy part anyway, but then i would have to get a diffrent tach :thud: and the mechanical tach probably would not fit in the factory location,then i would have to drill a hole in the fire wall,and that just leads to other whileImAtIt's :laughing:

I did RTFM :rolling: but it just did not make much sense to me :WTF

To Run My Sun Tach I Had To Buy A Msd Tech Adapter Since I Have A Msd Blaster Coil !!! To Make It Work !!
As For The Stock Tach Since Its A Gear Drive I Did Not Have Any Problems With It !!
I am also using the MSD Blaster HVC II coil.
My gear head son is running a MSD 6A box in his 75. We ran the tach off the box and removed the stock filter. Keep this for future use. Now he has both the stock tach and and big aftermarket one hooked up and they both work ok. Hope this helps.
Thanks Gary,

That was just the answer i was looking for :thumbsup:
That is exactly where i put my box,another forum member suggested it. Mounted the coil on the firewall between the brake booster and wiper motor,had a tough time finding a place for it,it's kinda big,bigger than i expected it is the MSD Blaster HVCII coil.
Thanks for the input Gary :thumbsup:

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